Quality-based Adaptive Video Over the Internet

IP networks and the Internet in general are subject to a wide range of fluctuations of the end-to-end bit rate available to applications. This uncertainty has motivated the development of adaptive appli- cations, i.e., applications that can adjust their resource requirements as a function of what the network can provide. In this paper, we explore an adaptation scheme that is not directly driven by these fluctuations, but based on the impact they have on the quality per- ceived by the application. Our focus is on the potential benefits of such a "quality-based" adaptation approach for video applications. We begin with a brief introduction of objective video quality as- sessment and its integration into an adaptive transmission system. Next, we discuss the joint impact of packet loss and encoding rate on video quality, based on which a simple quality feedback-control system has been built. Adaptation is carried out by measuring the quality of the received video and comparing it to a baseline refer- ence. Our preliminary experimental results show both the viability and the benefits of using video quality as the basis of adaptation. Possible directions of future research are also discussed at the end of the paper.